This page converts feet of water into torr using the factor 22.41984549, and shows the reverse figure alongside it. Both units measure pressure, which is why one number does the whole job.
One millimetre of mercury, used in vacuum work. Pump head expressed as a column of water — the way pump curves are drawn.
Gauge versus absolute. A tyre gauge reading 32 psi means 32 psi above atmospheric, which is about 46.7 psi absolute. Converting the number is straightforward; remembering which zero it was measured from is where the mistakes happen. N/mm² and MPa are the same size, so a drawing quoting either is quoting the same stress. The tables underneath give both a plain step-by-step lookup and a list of real quantities expressed in torr, so you can sanity-check whether your answer is a plausible size.
The formula
feet of water- The amount you are converting, in feet of water
22.4198454873- The exact number of torr in one foot of water
torr- The converted result
How it works, step by step
- Enter the value in feet of water.
- It is multiplied by 22.4198454873, the exact factor between the two units.
- The answer is shown in torr, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A steam boiler: 335 ftH₂O in torr
A steam boiler comes to about 335 ftH₂O. Multiplying by the factor: 335 × 22.4198 = 7510.65 Torr. Dividing the answer back by 22.4198 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
A bicycle tyre: 208 ftH₂O in torr
At 208 ftH₂O (a bicycle tyre), the same quantity in torr is 208 × 22.4198 = 4663.33 Torr. One foot of water is 22.4198 torr, so the numbers grow as expected.
How to read your score
Frequently asked questions
How many torr are in one foot of water?
Exactly 22.4198454873. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert feet of water to torr?
torr = feet of water × 22.4198454873. Reversed, feet of water = torr ÷ 22.4198454873, which is the same as multiplying by 0.0446033404007.
Which is the bigger unit, the foot of water or the torr?
The foot of water. One foot of water equals 22.4198 torr.
What does this quantity actually measure?
Both units measure pressure. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a foot of water?
Pump head expressed as a column of water — the way pump curves are drawn.
What is a torr?
One millimetre of mercury, used in vacuum work.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do ftH₂O to Torr in my head?
Plenty of people do this in their head: multiply by 22 instead of using the exact factor 22.41984549. At 100 that shortcut gives 2200 torr, off by 41.98 torr or about 1.87%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Feet Of Water to torr reference tables
| Feet Of Water | Torr |
|---|---|
| 0.5 ftH₂O | 11.2099 Torr |
| 1 ftH₂O | 22.4198 Torr |
| 2 ftH₂O | 44.8397 Torr |
| 3 ftH₂O | 67.2595 Torr |
| 5 ftH₂O | 112.099 Torr |
| 10 ftH₂O | 224.198 Torr |
| 20 ftH₂O | 448.397 Torr |
| 25 ftH₂O | 560.496 Torr |
| 50 ftH₂O | 1120.99 Torr |
| 75 ftH₂O | 1681.49 Torr |
| 100 ftH₂O | 2241.98 Torr |
| 250 ftH₂O | 5604.96 Torr |
| 500 ftH₂O | 11,209.9 Torr |
| 1000 ftH₂O | 22,419.8 Torr |
| 5000 ftH₂O | 112,099 Torr |
Exact factor: 1 foot of water = 22.4198454873 torr.
| Quantity | ftH₂O | Torr |
|---|---|---|
| Sea-level air | 33.9 ftH₂O | 760 Torr |
| A car tyre | 73.81 ftH₂O | 1655 Torr |
| Blood pressure, systolic | 5.352 ftH₂O | 120 Torr |
| A bicycle tyre | 207.6 ftH₂O | 4654 Torr |
| A domestic water main | 133.8 ftH₂O | 3000 Torr |
| A steam boiler | 334.6 ftH₂O | 7501 Torr |
Published reference values, converted with the same factor this page uses.